Immortals takes place after the mythological Titanomachy, a 10-year war between the Titans and Olympians fought long before the existence of mankind. When Titan Hyperion (Rourke) declares war on humanity, the Olympians are forced to stand on the sidelines in accordance with ancient laws. Even so, Olympian Zeus (Luke Evans) chooses not to remain idle, picking a human peasant named Theseus (Cavill) to defend humanity by tasking him with recovering the Epirus Bow, a powerful weapon created by the Olympian Ares (Daniel Sharman) that has the power to free the rest of the Titans from Tartarus, before Hyperion.